As the Deepwater Horizon drilling rig burned around him, Chris Pleasant hesitated, waiting for approval from his superiors before activating the emergency disconnect system that was supposed to slam the oil well shut at the bottom of the Gulf of Mexico.

The delay may have cost critical seconds. When Pleasant and his co-workers at rig owner Transocean finally got the go-ahead to throw the emergency disconnect switch, they realized there was no hydraulic power to operate the machinery.